PHP Class yii\caching\DbCache

By default, DbCache stores session data in a DB table named 'cache'. This table must be pre-created. The table name can be changed by setting [[cacheTable]]. Please refer to Cache for common cache operations that are supported by DbCache. The following example shows how you can configure the application to use DbCache: php 'cache' => [ 'class' => 'yii\caching\DbCache', 'db' => 'mydb', 'cacheTable' => 'my_cache', ] For more details and usage information on Cache, see the guide article on caching.

Since: 2.0

Author: Qiang Xue ([email protected])

Inheritance: extends Cache

Exibir arquivo Open project: yiisoft/yii2 Class Usage Examples

Public Properties

Property	Type	Description
$cacheTable		name of the DB table to store cache content. The table should be pre-created as follows: php CREATE TABLE cache ( id char(128) NOT NULL PRIMARY KEY, expire int(11), data BLOB ); where 'BLOB' refers to the BLOB-type of your preferred DBMS. Below are the BLOB type that can be used for some popular DBMS: - MySQL: LONGBLOB - PostgreSQL: BYTEA - MSSQL: BLOB When using DbCache in a production server, we recommend you create a DB index for the 'expire' column in the cache table to improve the performance.
$db		the DB connection object or the application component ID of the DB connection. After the DbCache object is created, if you want to change this property, you should only assign it with a DB connection object. Starting from version 2.0.2, this can also be a configuration array for creating the object.
$gcProbability		the probability (parts per million) that garbage collection (GC) should be performed when storing a piece of data in the cache. Defaults to 100, meaning 0.01% chance. This number should be between 0 and 1000000. A value 0 meaning no GC will be performed at all.

Public Methods

Method	Description
exists ( mixed $key ) : boolean	Checks whether a specified key exists in the cache.
gc ( boolean $force = false )	Removes the expired data values.
init ( )	Initializes the DbCache component.

Protected Methods

Method	Description
addValue ( string $key, string $value, integer $duration ) : boolean	Stores a value identified by a key into cache if the cache does not contain this key.
deleteValue ( string $key ) : boolean	Deletes a value with the specified key from cache This is the implementation of the method declared in the parent class.
flushValues ( ) : boolean	Deletes all values from cache.
getValue ( string $key ) : string \| false	Retrieves a value from cache with a specified key.
getValues ( array $keys ) : array	Retrieves multiple values from cache with the specified keys.
setValue ( string $key, string $value, integer $duration ) : boolean	Stores a value identified by a key in cache.

Method Details

addValue() protected method

This is the implementation of the method declared in the parent class.

protected addValue ( string $key, string $value, integer $duration ) : boolean
$key	string	the key identifying the value to be cached
$value	string	the value to be cached. Other types (if you have disabled [[serializer]]) cannot be saved.
$duration	integer	the number of seconds in which the cached value will expire. 0 means never expire.
return	boolean	true if the value is successfully stored into cache, false otherwise

deleteValue() protected method

Deletes a value with the specified key from cache This is the implementation of the method declared in the parent class.

protected deleteValue ( string $key ) : boolean
$key	string	the key of the value to be deleted
return	boolean	if no error happens during deletion

exists() public method

This can be faster than getting the value from the cache if the data is big. Note that this method does not check whether the dependency associated with the cached data, if there is any, has changed. So a call to [[get]] may return false while exists returns true.

public exists ( mixed $key ) : boolean
$key	mixed	a key identifying the cached value. This can be a simple string or a complex data structure consisting of factors representing the key.
return	boolean	true if a value exists in cache, false if the value is not in the cache or expired.

flushValues() protected method

This is the implementation of the method declared in the parent class.

protected flushValues ( ) : boolean
return	boolean	whether the flush operation was successful.

gc() public method

Removes the expired data values.

public gc ( boolean $force = false )
$force	boolean	whether to enforce the garbage collection regardless of [[gcProbability]]. Defaults to false, meaning the actual deletion happens with the probability as specified by [[gcProbability]].

getValue() protected method

This is the implementation of the method declared in the parent class.

protected getValue ( string $key ) : string \| false
$key	string	a unique key identifying the cached value
return	string \| false	the value stored in cache, false if the value is not in the cache or expired.

getValues() protected method

Retrieves multiple values from cache with the specified keys.

protected getValues ( array $keys ) : array
$keys	array	a list of keys identifying the cached values
return	array	a list of cached values indexed by the keys

init() public method

This method will initialize the [[db]] property to make sure it refers to a valid DB connection.

public init ( )

setValue() protected method

This is the implementation of the method declared in the parent class.

protected setValue ( string $key, string $value, integer $duration ) : boolean
$key	string	the key identifying the value to be cached
$value	string	the value to be cached. Other types (if you have disabled [[serializer]]) cannot be saved.
$duration	integer	the number of seconds in which the cached value will expire. 0 means never expire.
return	boolean	true if the value is successfully stored into cache, false otherwise

Property Details

$cacheTable public_oe property

name of the DB table to store cache content. The table should be pre-created as follows: php CREATE TABLE cache ( id char(128) NOT NULL PRIMARY KEY, expire int(11), data BLOB ); where 'BLOB' refers to the BLOB-type of your preferred DBMS. Below are the BLOB type that can be used for some popular DBMS: - MySQL: LONGBLOB - PostgreSQL: BYTEA - MSSQL: BLOB When using DbCache in a production server, we recommend you create a DB index for the 'expire' column in the cache table to improve the performance.

public $cacheTable

$db public_oe property

the DB connection object or the application component ID of the DB connection. After the DbCache object is created, if you want to change this property, you should only assign it with a DB connection object. Starting from version 2.0.2, this can also be a configuration array for creating the object.

public $db

$gcProbability public_oe property

the probability (parts per million) that garbage collection (GC) should be performed when storing a piece of data in the cache. Defaults to 100, meaning 0.01% chance. This number should be between 0 and 1000000. A value 0 meaning no GC will be performed at all.

public $gcProbability